Do manufacturers limit hard drive capacity?

kyot56Oct 2, 2006, 5:20 AM

First off, I hope this is the proper forum (if not, sorry mod).

Okay, so I'm reading the Sunday paper ads, hoping for some stellar hard drive bargain and I come across the Office Depot ad showing a Maxtor 100 gig drive for $19 after rebate. Now I am wondering "Why does someone still make a 100 gig drive when 250 or ever 500 gigs are available?" The economics just don't seem right, having all these different sized drives coming out of the factory.

So my question is, are all or most hard drives actually capable of being these 250+ gig drives, and it's just the manufacturers somehow limiting the size so it will only appear as 100 gig, etc? If so, is there a way to change this and basically get a larger-than-advertised drive? Hey, for $19, I'd be willing to give it a try if I knew what to do. Anyone have any ideas/opinions?Thanks

I'm not sure about all the technical specifics of it, but I'm sure that it costs more to make larger drives as they do use higher density disk platters, and the manufacturing process has got to involve more. Another basic reason higher capicity HDDs cost more is just because you get what you pay for. It's a very simple business concept to offer something inferior at a base price, and then to charge more for a better product(higher storage capacity, faster seek time).It's impossible to get a HDD to recognize more space than it was designed to hold, as the stated capacity is physically all there really is.

Some hard drives are still in small capacities because the the initial stock has not been depleted. Another reason can be the the factories that make the smaller hard drives work at almost 100% success rate, so the company is making a large profit from the small capacities (because the equipment has already been payed off and all the bugs are out).

For some of the larger sizes, there probably are some sections that are limited in capacity. Like 700GB vs 750GB. It could be that there was a major defect on that part of the platter or a few small defects that when ignored don't affect normal operation.

I don't think there is anyway for you to "unlock" capacity on your drive and if possible I would not recommend it.

It's impossible to get a HDD to recognize more space than it was designed to hold, as the stated capacity is physically all there really is.

First my knowledge of hard drive manufacturing is very small, but do you think that the data density on the platter is different for each size hard drive because i would suspect that there would be difficulties with implementing that. Each size hard drive would need to have a slightly different mechanism and programming for accessing the data while the manufacturing would need to be continuously changed.

From what little I know, it does vary how much data is on each platter depending on HDD size. Also, in the last several years platters have gotten smaller(as small as 1") and larger drives will simply have more platters, each with higher density, due to utilizing newer technology such as the perpendicular recording found in Seagate's largest drives. I'm sure it does take a diffently adjusted mechanism to read HDDs of different sizes, but I'm also sure that the cost of developing each new, higher capacity drive is more than recovered when people buy them!

From what little I know, it does vary how much data is on each platter depending on HDD size.

As I understand it, within one drive family the only thing that usually varies is the number of platters: if you have 150GB per platter, then you can make 150GB, 300GB, 450GB, 600GB and 750GB just by installing a different number of platters. Don't think anyone uses more than five these days.

Just was researching some on hard drives. Here's a few quotes that stuck out.

Quote:

Each platter has two surfaces that are capable of holding data; each surface has a read/write head. Normally both surfaces of each platter are used, but that is not always the case. ...Newer drives...sometimes leave a surface unused for marketing reasons--to create a drive of a particular capacity in a family of drives.

Quote:

Drives with many platters are more difficult to engineer due to the increased mass of the spindle unit, the need to perfectly align all the drives, and the greater difficulty in keeping noise and vibration under control. More platters also means more mass, and therefore slower response to commands to start or stop the drive; this can be compensated for with a stronger spindle motor, but that leads to other tradeoffs.

I've read quite a few websites which say that some pre-built systems from big manufacturers (HP, Dell etc...) all have the same hard drive, but is locked by firmware to display a certain size only. They might not do this any more, but apprently they used to. Google it - I was trying to find out how to fix the firmware of a 160gb Maxtor I got given (it shows up as a 'Maxtor Calypso', it's internal product family), oh if anyone knows how to flash hard drive firmware please PM or whatever me!

I once worked for a pre-built computer company. They had a program that would 'destroke' a drive down in capacity. Say the customer wanted a 40 gig drive but all we had were 80 gig drives. They could use this program to limit the size to 40 gig even though the stickers still showed 80 gig on the drive. So yes you could unlock the full capacity, but only to the drives origional manufactred size.

Most hard drives are, as stated above, a series of circular platters. Each platter has a predefined size. For example, most manufacturers today use 80 or 100 Gigabyte platters. To add capacity a manufacturer adds platters to reach the desired size. It is more complex than this, as there are many more components that must be added (as well as a different drive firmware) but I'm saying this just to keep the concept simple.

There are many cases where hard drives are manufactured at greater capacities than which they are sold as. These are firmware limited drives. Most of these drives have one side of a platter, or an entire platter disabled in the firmware. For example, it is possible to unlock certain Maxtor Diamondmax 10 250GB drives to the full 300GB because they come with all 3 platters, just with one side of the last platter disabled.

There are some risks involved with this though. Many manufacturers, hard drive, memory, cpu, etc... will limit the speed or capacity of a component because it could not "make the cut" at its designed rating. Instead of junking the units and making them "yield casualties" a manufacurer will determine what downgraded rating the unit can handle reliably to meet quality control specs and label it as such. By "reliably" I mean that a manufacturer will always play it safe and downgrade a products rating a bit more than it really needs to. This also applies to processors and memory as well.

The risk in unlocking a drive like this, is that most often when you do this the drive will not run reliably. How much you get out of a drive like this is purely "luck of the draw". Some may unlock and work flawlessly and some may unlock and be unusable.

It is also worth mentioning that every drive can be "unlocked" as they all have a portion of extra space dedicated to remapping bad sectors to clean ones. Unlocking and using this space, though, usually does not benefit you... especially if your boot sector were to fry at some point.

One last thing of note. A hard drive will NEVER appear in Windows at its advertised capacity. The reason for this is that Hard Drive manufacturers measure space in decimal (base 10) gigabytes while a computer will always measure the same space in binary (base 2) gigabytes. Since a decimal gigabyte is 1000 megabytes (which is 1000 kilobytes, which is 1000 bytes) and a binary gigabyte is 1024 megabytes (1024KB -> 1024 bytes) this adds up to A LOT of percieved lost space. This is why a 80 gig drive shows as 74, and a 100gig drive usually shows as 92 in Windows. For a 100 gig drive it comes out to be 100,000,000,000 bytes versus 107374182400 bytes. Thats almost a 7.5% difference.